<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
  <script src="../vue.js"></script>
</head>

<body>
  <div id="app">
    <h1>计数器{{count}}</h1>
    <button @click="add">直接累加</button>
    <br>
    <button @click="decrement($event)">每次累减</button>
    <br>
    <button @click="addN(2,$event)">每次累加2</button>
  </div>
  <script>
    Vue.config.productionTip = false;
    
    const vm = new Vue({
      el: "#app",
      data() {
        return {
          count:0
        }
      },
      methods:{
        add(e){
          console.log(e,'add中的e');
          this.count+=1
        },
        decrement(e){
          console.log(e,'decrement中的e');
          this.count-=1
        },
        addN(n,e){
          console.log(e,'addN中的e');
          this.count+=n
        }
      }
    })
  </script>
</body>

</html>